Atrophy is partial and special in its operation, nanism is general.    From Wordnik.com.  [Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants] Reference

Again, atrophy is to be separated from that general diminution in the size of the whole plant or of distinct parts of that plant which is comprised under the term "nanism.".    From Wordnik.com.  [Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants] Reference

A characteristic phenomenon is nanism: in Sardinia there are some species that are smaller than those living outside the Island, such as the small horses on the Giara plateau, or Sardinian deer, smaller than their European "cousins".    From Wordnik.com.  [WN.com - Articles related to BP inks deal to save turtles from oil spill] Reference